We propose to evaluate the impact of a unique anti-poverty program in Mexico on the health and cognitive development of young children. The program, PROGRESA, combines a traditional cash transfer program with financial incentives for families to invest in the human capital (health, education and nutrition) of their children, and thereby break the intergenerational transmission of poverty. To receive the cash transfers, pregnant women must obtain prenatal care and nutrition supplements, children age 0-5 must obtain well-baby care and participate in growth monitoring and nutrition supplement programs, and families must participate in health nutrition and hygiene education programs. Our analysis will take advantage of a randomized controlled design. In 1998, 506 villages were randomly assigned to control and treatment groups. Eligible households in treatment villages received benefits immediately, while benefits for eligible households in control villages were postponed until after the year 2000. A pre-intervention baseline survey of approximately 19,000 households with over 95,000 individuals and four follow-up surveys (at six month intervals) of the same households were conducted over the two-year experimental period. We propose to conduct a follow-up survey of the same households in 2003. This follow-up survey will be three years after the experiment ended and it will include biomedical measures of child health status and of cognitive development. We will use this unparalleled experiment to examine the following specific questions for children who were age 0-3 at baseline and born during the experimental period: 1. Did PROGRESA improve child health, nutrition and cognitive development? 2. Are the observed differentials sustained 3 years after the enrollment of all children into PROGRESA 3. Could the same results have been achieved through just cash transfers with the requirements for care and monitoring, but without the nutrition supplements?